The present invention relates to a device for feeding medication into trees or the like and, more particularly, to such a device that is implanted in an opening or hole in the trunk or stem of a tree.
Trees are treated for various diseases or deficiencies by the introduction of medication into the tree itself. One method of introducing the medication into a tree is to drive a capsule containing the desired medication into the trunk of the tree, enabling the phloem layer of the tree to absorb the medication from the capsule. A problem in designing a medication containing capsule for such a use is that the medication must be retained in the capsule until it is inserted into the tree and yet once the capsule has been inserted, the medication must be freed from the capsule to be absorbed by the tree.
U.S. Pat. No. 1,999,458 attempts to solve this problem by providing a hollow capsule with openings which are covered by film-like coverings that are disrupted or worn away by friction between the wall of the capsule and the hole in the tree. This method of solving the problem requires that there be an appropriate interference fit between the hole in the tree and the capsule and that the film-like coverings have not flowed into the openings but have remained on top of the openings to insure that the openings are opened by the friction.
Another problem associated with the use of a medication capsule inserted into the trunk of a tree, is the defense mechanism of the tree which builds up sap pressure at the intrusion of a foreign object, such as a medication capsule, in an attempt to eject the foreign object from the tree.
Yet another problem associated with the use of medication capsules inserted into trees is the post-treating of the tree after the capsule is in place. Once the capsule is inserted into the trunk of the tree, the resulting hole must be closed and a tree wound dressing must be applied to help the tree heal and prevent insects from attacking the tree at the wound.
The above-identified problems have been alleviated by the tree medication capsule in U.S. Pat. No. 3,706,161 which comprises elongated slots sealed with a sap soluble material to retain the medication within the capsule until it is inserted into the tree. The capsule is provided with anti-rejection barbs which engage the tree upon insertion of the capsule therein to prevent it from being ejected by the sap pressure. To close the hole in the tree, the capsule has an enlarged outer end portion with a ring of tree wound dressing thereon so that the hole in the tree is closed when the capsule is driven into it. While the tree medication capsule of U.S. Pat. No. 3,706,161 has generally served its intended purpose, its construction has not ensured that an effective amount of medication is released into the tree in all cases. Also, its generally flat inner end has sometimes made it difficult to insert the capsule into a tree opening.
The tree implant device of the present invention is not subject to any of the disadvantages of the prior art devices and possesses many advantages over the prior art devices.